Modern gas and diesel internal combustion engines require precise control of fuel delivery to a combustion chamber in order to operate at peak performance (such as efficiency, power, reliability, etc.). This fuel control is typically accomplished via a fuel injector, which provides a mechanism for reliably and accurately injecting fuel into the combustion chamber of internal combustion engine, such as one found in automotive and truck engines, for example. Fuel injectors require frequent service to operate efficiently in dispersing precise amounts of fuel into the combustion chamber. The life cycle of the fuel injector depends on the ability to provide consistent fuel pressure and cylinder head pressure to deliver fuel at incremental moments as determined by the engine's controls and requirements.
Fuel injectors are typically mounted onto an engine either by inserting a threaded injector into a tapped hole or by a retaining assembly, and they are positioned such that the injector can deliver fuel directly into the combustion chamber. The retaining assembly typically consists of a small dual fork-like object that straddles the fuel injector and is secured via a mounting bolt that passes through a hold-down bolt hole in the valve cover and into a threaded mounting hole in the cylinder head.
To repair or remove such a fuel injector, one normally must remove the mounting bolt that passes through the valve cover that is secured to the cylinder head. The retaining fuel injector fork is then removed with the mounting bolt and replaced with a fuel injector removal tool that passes through the same hold-down bolt hole in the valve cover and is secured to the cylinder head via the threaded mounting bolt hole in the cylinder head. The fuel injector removal tool typically has a separate fork that fits onto and around machined flats in the side of the fuel injector. An additional fastener is threaded into the top of the assembly. By rotating the additional fastener, the fork is raised, which raises the fuel injector and allows the user to remove the fuel injector.
This method has its own problems, however. First, it requires passing the fuel injector removal tool through the hold-down bolt hole in the valve cover and threading and unthreading it into the threaded mounting hole in the cylinder head assembly, which creates an opportunity for the tool to damage or get stuck in the mounting hole. Either problem will greatly increase the time and cost of replacing the fuel injector. Second, the process is more time-consuming than it needs to be, because the fuel injector removal tool must pass through the valve cover injector mounting hole and then be screwed and unscrewed from the cylinder head.